For reasons of esthetics and hygiene, the work areas, hallways and stair within both commercial and public buildings, as well as shopping malls are increasingly being laid with natural and stoneware tiles and flags.
In order to avoid accidents due to tripping and slipping, these floor coverings are required to meet certain requirements, with respect to their sureness underfoot. Thus, these flooring coverings are required by the statutory provisions (the guidelines of the German Workplaces Ordinance) to be level, slip resistant, and easy to clean.
The term ‘stoneware’ is representative of hard-fired tiles and flags which maybe glazed or unglazed, with or without, a fired ceramic surface coating. In accordance with the DIN Standard, there is a subdivision according to water absorption and production method. DIN EN 176 defines stoneware tiles and fine-stoneware tiles (porcelain tiles).
For the slipproof properties, however, it is the surface roughness which is critical. Consequently, the data sheets of the German trade association (ZH 1/571) and of the German municipal accident prevention authorities (GUV 26.17; 26.18) specify precisely defined nonslip classes (R classes) for the various areas of application, with higher R values standing for greater slip inhibition.
The R values are determined in accordance with DIN 51 130 in tests on a sloping plane, and are reported in incline angle ranges: R 9=3°-10° incline angle; R 10=10°-19° incline angle; R 11=19°-27° incline angle; R 12=27°-35° incline angle; R 13=>35° incline angle.
For profiled flags and tiles, additionally, the displacement volume (V) is reported in accordance with DIN 51 130. The displacement volume is the volume between the upper walking plane and the lower water removal plane. The displacement volume lies between V 4 (=4 cm3/dm2) and V 10 (=10 cm3/dm2).
For areas with increased risk of slippage, i.e., areas in which floors and steps come into contact with friction-reducing and/or slip-promoting media such as, for example, water, wastes, starchy residues, animal and vegetable fats or oils, mineral fats or oils, soaps, pigment dirt, abraded rubber, and silicones, the appropriate evaluation groups are R>10, especially, R 12 and R 13.
Tiles and flags are generally considered as easy to care for and pleasant to clean. This is undoubtedly true of level, smooth and hard substrates of R classes 9 to 11. As the R class goes up, however, the roughness of the surfaces increases. Those considered problematic are slightly rough substrates of class R 12 and, in particular, profiled tiles and flags of classes R 12 to R 13 and V 8 to 10, known as fine-stoneware tiles/flags.
Cleaning effort is increased considerably as the roughness/unevenness of the substrate increases, especially if porosity results in additional increase in the size of the surface.
There has therefore been no lack of attempts in the past to develop new cleaning methods, in addition, to the special mechanical cleaners, and, in addition, to minimize cleaning effort and optimize the cleaning effect by means of universally applicable all-purpose cleaners, especially detergents tailored precisely to the particular type of flooring and type of soiling.
Commercially customary detergents for manual and machine cleaning are, generally speaking, complex mixtures of anionic, nonionic and amphoteric/zwitterionic surfactants which comprise customary auxiliaries and additives such as alkalis, complexing agents, solubilizers, chlorine bleaching lye additives, and, if desired, mild abrasives. The commercially customary detergents are employed in concentrations from about 0.5 to 10% by weight
In practice, however, it has been found that it was often impossible to remove the soiling fully in the first pass, even with great mechanical assistance through the use of microfiber pads, scrubbers, or high pressure apparatus, abrasive suction rollers or brush rollers, and additional intensive rinsing with water, on the problematic fine-stoneware substrates. Additional cleaning steps were necessary.
Apart from the considerable additional expense on operatives and machinery, and the additional environmental burden of detergents, the abrasive action of the mechanical exposure reduces more quickly the sureness of the floor covering underfoot
EP-B-0 928 829 describes detergents comprising mixtures of at least the following four components:    a) at least one quaternary ammonium compound having a C1-6 hydrocarbon radical and three alkoxy groups,    b) at least one water-soluble alkaline substance from the group consisting of alkali metal hydroxides and alkanolamines,    c) at least one alkylpolyglycoside, and    d) at least one solubilizer from the group consisting of water-soluble alcohols and glycol ethers,which were designed specifically for the cleaning of hard surfaces, especially vertical surfaces, and which when mixed with water are said to give a thickening solution having rheopexic properties. Through selection of components a), b), c) and d) and their concentrations it is possible to control the rheopexy and the foam behavior. There is no reference to the specific problem of the cleaning of fine-stoneware tiles and the effect of improved spreading through alkoxylated ammonium compounds.
GB-A-2 334 723 describes detergents for glass, smooth, bright and glossy surfaces, consisting of one or more ethoxylated quaternary ammonium compounds, at least one glycol ether and/or C1-22 alcohol and at least one anionic surfactant. The detergent is said to leave no spots or streaks after cleaning, and to have antimicrobial and antistatic properties. There is no reference here either to the specific problem of the cleaning of rough, non-glossy profiled surfaces, or to the effect of improved spreading through alkoxylated ammonium compounds.
DE-A-100 38 198 provides for the use of aqueous detergent concentrates based on nonionic, anionic, amphoteric surfactants, with or without, the use of customary auxiliaries and additives, said concentrates comprising alkoxylated amine compounds of the general formula[R1, R2, R3, R4N]+X—where    R1 is a straight-chain, optionally branched, alkyl radical, optionally containing multiple bonds, having from 8 to 22 carbon atoms,    R2 is —(CH2CHR5O)n—R6 where R5=H, —CH3 or —C2H5; R6=H, —CH3, —C2H5, —C3H7 or —C4H9, and n=1 to 25,    R3 is R1 or R2,    R4 is —CH3 or —C2H5, and    X— is an anionic radical, especially methyl sulfate, ethyl sulfate, phosphate, chloride, bromide or iodide as cleaning enhancers for cleaning fine-stoneware tiles.
The ethoxylated quats, which are no longer acceptable from an environmental standpoint, do indeed display good cleaning enhancement properties; however, they no longer conform to the requirements for surfactants in detergents. Moreover, the ethoxylated quats do not achieve the required values for biodegradation according to OECD 301 A-F. The cationic surfactants used additionally in DE-A-100 38 198 or U.S. Pat. No. 5,929,024 are ethoxylated alkylamido-alkyl-dialkylammonium salts, of which it is known that they are firstly problematic and cannot be prepared without objectionable by-products and that they exhibit an increased aquatic toxicity and also a poorer total degradation than the nonionic and/or anionic surfactants customarily used.
Ethoxylated quats can be irritating on skin contact, and some of these compounds may even be toxic to aquatic organisms. Compatibility with materials is also not a given on a variety of surfaces. Here, particular mention may be made of metallic surfaces, on which cationic surfactants, even on stainless steel, lead to corrosion phenomena, and particularly to pitting. Critical to this effect are the counterions, mostly chloride ions.
In modern detergents, therefore, ethoxylated quats are no longer tolerated, on account of their increased environmental risk.